SIGIRR and neoplasm: Therefore, the results showing that M1-macrophage polarization, directly induced by MMTV-neu/IL-1R8−/− tumors or indirectly induced by leukocytes recruited in the tumor, such as NK cells, DCs and CD8+ T lymphocytes, may also account for reduced tumor growth and metastasis observed in MMTV-neu/IL-1R8−/− mice.